1. Field of the Invention
The present invention relates to an image display apparatus and more particularly to an image display apparatus using a reflective image display element.
2. Description of the Related Art
In a known image display apparatus using a reflective liquid crystal panel (image display element), respective optical paths of light incident upon and light emergent from the liquid crystal panel need to be made different from each other. For that purpose, a polarizing beam splitter allowing P-polarized light to pass through it, but reflecting S-polarized light is arranged on the incident/emergent surface side of the reflective liquid crystal panel. The characteristic of a polarization splitting film used in the polarizing beam splitter depends on the incidence angle of the incident light. As the incidence angle of the light incident upon the polarization splitting film departs from 45° to a larger extent, leakage light from the polarization splitting film is increased and the contrast of a projected image is reduced. The term “leakage light” implies light entering a projection lens when the liquid crystal panel is driven in a mode where all pixels are displayed black.
There is known a technique of arranging a polarizer, which cuts off the leakage light, on the emergent surface side of the polarizing beam splitter in order to increase the contrast of the projected image. However, the known technique has the problem that brightness of the projected image is reduced because a polarizer has low transmittance.